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Re: Space Shuttle - Flight

Postby eatdirt » Thu Jun 20, 2019 8:33 pm

Thanks Gingin, yes, my first TAL was indeed a bit wild...

I got scared at some point as the AP was pushing me into the qbarmax warning messages, then I took CSS to pull up and lost too much energy. I did a straight-in landing in full manual to compensate afterwards. The landing itself was crabby, braking right only and rudder pushed right to maximum, miracle I still was on the runway at the end :)

Thanks for the help for the manual MECO, I got it now!
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Re: Space Shuttle - Flight

Postby GinGin » Sun Jun 23, 2019 11:10 am

Coming back to Vandenberg Early in the morning

Image


Image


Sonic Boom

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Wet grass at Dawn

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Re: Space Shuttle - Flight

Postby legoboyvdlp » Sun Jun 23, 2019 2:04 pm

Ooh - amazing clouds! Nice shots :D
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Re: Space Shuttle - Flight

Postby eatdirt » Sun Jun 23, 2019 9:56 pm

SOTM winning pictures, astonishing!!!
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Re: Space Shuttle - Flight

Postby Thorsten » Fri Jun 28, 2019 9:56 am

Just computed another flight to HST (with a little more external computing power applied...)

The good news:

* I got there with 43 % propellant left in the OMS tanks, and I believe one can even be a bit more fuel-conservative with more careful phasing - the amount seems enough to de-orbit

* during phasing, I could reliably see that the apoapsis was always the same amount (2300 m) above the target, so I can't reproduce the non=periodicity GinGin has seen

* again the Lambert solver did a fairly decent job for the terminal phase

* save/resume worked okay during the mission, I have several saved points along the way, and I seem to be able to resume from them fine

The bad news:

* the on-board solver refused to produce a PEG-4 insertion solution which LEO targeting had computed correctly - need to investigate

* upon handover to the detailed model, HST should have been 4000 m above me, but for some weird reason it appeared on the same altitude - need to investigate, that bug completely screwed the deceleration plan...
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Re: Space Shuttle - Flight

Postby eatdirt » Sat Jun 29, 2019 6:26 pm

Hi Thorsten,
the amount seems enough to de-orbit


I confirm, got also a bit more than 40% and I successfully deorbit afterwards to a viable reentry, but this is on the boundary, OMS tanks were at 1% after the deorbit burn.

need to investigate, that bug completely screwed the deceleration plan...


I have problems too when the deceleration burn is within the detailed zone, I made it by two T2 burns, one outside the detailed zone, and another one inside.

Cheers,
chris.
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Re: Space Shuttle - Flight

Postby GinGin » Tue Jul 02, 2019 6:55 am

Thanks for the sum up and flight reports , entertaining .

@Thorsten : Glad to see you had no trouble with periodicity .
Until which relative down range did you observe a coherent periodicity ?
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Re: Space Shuttle - Flight

Postby Thorsten » Tue Jul 02, 2019 9:11 am

I have problems too when the deceleration burn is within the detailed zone, I made it by two T2 burns, one outside the detailed zone, and another one inside.


It should be easiest to par at an rbar position a few km behind and then come in nice and slow at the same altitude.

Until which relative down range did you observe a coherent periodicity ?


Over 3 orbits, starting from 600 km out to the last apsis 40 km out, with altitude separations ranging from 30 km to less than 10 km.
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Re: Space Shuttle - Flight

Postby Vinny002 » Thu Jul 04, 2019 11:00 pm

I am really getting hang of flying around in space with the FG space shuttle!!
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Re: Space Shuttle - Flight

Postby Vinny002 » Fri Jul 05, 2019 7:04 pm

The launch went very well, until about an hour into the flight! In about an hour into the flight, the RCS or the OMS engines started firing unexpectedly and lowers the perigee well inside the earth! How to solve this issue? Thanks!

Cheers,
Vincent
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Re: Space Shuttle - Flight

Postby GinGin » Fri Jul 05, 2019 7:58 pm

Hey Vincent, please post your trouble in the help thread ( with a bit more explanations of the situation ;) )

https://forum.flightgear.org/viewtopic.php?f=87&t=35079

@Thorsten and EatDirt: I would be very curious next time you do a Rendez Vous to have some screen of your rendez vous canvas.
I find that entertaining to see different ways to get to a same place :)
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Re: Space Shuttle - Flight

Postby Thorsten » Sat Jul 06, 2019 6:20 am

I would be very curious next time you do a Rendez Vous to have some screen of your rendez vous canvas.


I actually kept some from the last test.

So here's the 'three orbit, gradually raising periapsis' way of doing it (including a judgement error :oops: )

Launch delivered us some 600 km behind HST and some 2.4 km above at apoapsis, so insertion is done into an orbit with periapsis some 45 km lower - this leads to a rapid catch-up, so at next apsis the periapsis is raised again to avoid over-shooting HST...

Image

... and we arrive in the 100 km region (note the same apoapsis 2.4 km above target, just drawn to different scale. Here I had already made my error of judgement in not bringing periapsis up enough...


Image

... so after save/resume a day of real time later, I find that I need to commit another 30 fps to correcting this - that's not a nice terminal burn :?

Image

It got there though, and if eatdirt is correct with just enough propellant left to go home (I haven't tried myself, I got side-tracked with LEO targeting...)
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Re: Space Shuttle - Flight

Postby GinGin » Sat Jul 06, 2019 6:21 pm

Wow Thanks.
Exactly what I am looking for in flight " Debrief" :)

Quick note, for those Delta height , I also observe a correct periodicity.
What I observed as "un" forecasted periodicity are when the delta height is reduced to 80 kft and below.

Anyway, I got a free week next week and I will have time for more tests and fun on Hubble :)


Some nice screens of my last RTLS, with Sun playing with Oil picturers

Image



Image
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Re: Space Shuttle - Flight

Postby legoboyvdlp » Fri Jul 12, 2019 8:01 pm

Image

On the way to ISS 8) Thanks to GinGin for help - I will need to cheat though, ended up about 2 degrees off inclination at MECO, not sure why.
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Re: Space Shuttle - Flight

Postby Thorsten » Thu Aug 01, 2019 2:50 pm

Capturing the Spartan-201 Satellite- starting from 1500 m distance.

A v-bar approach - first view of the Satellite in the COAS recticle - combined with radar this gives some situational awareness.

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Now pretty close, seen through the pilot window:

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Rotating the Shuttle around such that the RMS arm can reach the grappling point, Eileen holds the position while I fish for the satellite:

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And the Spartan goes into the bay:

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Payload retention latches are closed, the RMS arm can be disconnected

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Crew takes a short break before stowing the RMS arm again

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The whole workflow (even using the rendezvous display and external view) is surprisingly difficult, I didn't even attempt this using internal views only, the situational awareness is very poor ('where did the damn thing go now???'). Eileen makes the whole thing possible, but still not easy. Definitely needs more training, but is a fun way to spend 90 minutes.
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